Rotary gate valves of various forms are used both as pure shut-off valves and as flow-regulating valves. These rotary gate valves are used particularly frequently below the outlets of bulk material silos, in conveyor pipes, in pneumatic conveyor troughs and channels and the like.
In these known constructions a multi-part gate valve housing is generally provided in which a gate valve rotor is arranged so that it extends at right angles to the material flow direction, its shaft being rotatably mounted in opposing side walls of the housing, and it has an approximately part-cylindrical sliding part which serves as the actual shut-off or flow-regulating element for the flow passage cross-section. This rotor can be rotated about its shaft in the desired manner by hand or by a motor. A sealing arrangement which co-operates with the outside of the said sliding part to form a seal is also located inside the gate valve housing. Such a sealing arrangement usually has sealing elements which are made from metal or elastic materials and should butt against the moving surfaces of the sliding part by sliding or rubbing and form a seal. Therefore all the sealing elements are subject to more or less great wear and thus have to be adjusted or replaced relatively frequently. In the known rotary gate valve arrangements, in order to replace the sealing elements intermediate pieces (compensators or the like) have to be removed and sealing flanges dismantled, which is frequently very costly and awkward.
In addition, in the known rotary gate valve arrangements, because of the construction of the sealing arrangements and sealing elements, there are parapet-like steps which inhibit the flow of material through the housing. In the case of gate valve housings which are arranged approximately horizontally or slightly inclined and are constructed like pneumatic conveyor channels this is a particular disadvantage because only an insufficiently large total region of the housing base can be constructed for the admission of aerating air.